NostalgiaGen

NostalgiaGen 0.6 - Generate Minecraft Alpha/Beta worlds

"NostalgiaGen brings the awesome old Minecraft generators to your Sponge/Forge server. If you have an old world seed from the early days of Minecraft Alpha or Beta you would like to play on again this is now possible! NostalgiaGen generates worlds usually 99% identical with the original Minecraft world when using the same seed."

Supported generators

 - Minecraft Alpha 1.1.2_01

 - Minecraft Beta 1.7.3 (The generated terrain is equal to the generators of Minecraft Alpha 1.2.0+, however things like trees or ores might be located at different positions.)

More information and FAQ here. This is a mod by Minecrell, submitted to the Sponge forums. I have personally emailed him and gotten permission to upload it here.